One day, although it is not clear that a good part of us will see it, systems with a speed of one terahertz will exist. Now, the path that still separates us from that milestone is long and tortuous, so each step along the way is something to highlight. And it is that as the speed increases, so does the complexity, and in this case we are talking about a jump that forces us to face a challenge that has been in force for a long time.
An example of such complexity we find it in evolution to overcome the limits of silicon, the semiconductor that for decades has been responsible for the evolution of computing and technology. And it is because we have been talking for many years, for example, about carbon nanotubes, which will allow us to continue advancing in reducing the size of the elements that make up the integrated ones. Let us remember that, to avoid electrical leaks, silicon cannot go below three nanometers (at least in theory). However, we will still have to wait, except for surprise, for the arrival of nanotubes.
This, with so many years of research, “only” (I put it in quotes because it’s a great achievement, really) to be able to jump from three to two nanometers, so imagine the technological evolution that is necessary to be able to move from 5, 2 gigahertz that we can currently find in an Intel Core i9-12900K up to a terahertz. Let’s remember that a terahertz is a thousand gigahertz, so we talk about multiply current speed by 200.
so here we are no longer just a problem of size, but also of materials. Semiconductors, and especially silicon, have proven exceptionally useful so far, and will continue to do so in the short to medium term. However, just as we are already approaching its limits in terms of size, sooner or later we will also do so in terms of its maximum speed. In other words, the terahertz cannot be reached with semiconductors, the use of superconductors will be necessary.
There are, however, two problems with this type of material: its lack of unidirectionality and its demands in the thermal section, two complex problems that must be resolved to continue advancing towards the terahertz. To understand it, there are some concepts of the physics of semiconductors and superconductors that you should know, and that will also help you understand the reason why semiconductors have been and are the kings of electronics.
As you can tell just from their names, the conductivity conditions of semiconductors are lower than those of superconductors. However, by its nature, allow to define, when applying a certain voltage, a unidirectional flow that allows channeling the “traffic” in the desired direction. For decades, something similar has been attempted with superconductors, in order to take advantage of their better conductivity, but until now it had not been possible.
I say until now, because a recent study carried out by researchers at the Delft University of Technology has managed to take a giant step, by using a specific material that would allow direct regulation of electrical transit through the superconductor. It is the researchers themselves who sign this achievement who relate it, directly, with the possibility of creating integrated with speeds that can reach the terahertz.
There is, however, another fundamental challenge: temperature. And no, unlike current chips, I am not talking about its dissipation, because one of the advantages of superconductors over semiconductors is that, when used at their critical temperature they become perfect conductors, that is to say, that the resistance becomes zero, so that the current can flow infinitely without decaying, without any loss. The problem, of course, lies in that critical temperature.
The critical temperatures of superconductors are low, very low. In fact, the current goal of this research team is make your technology capable of operating at full capacity at temperatures above 77 degrees Kelvin (-196.15 degrees Celsius), since that temperature could be maintained using liquid nitrogen. However, at the moment the required temperature is much lower. Thus, at least for now, the terahertz is still far from beginning to become a reality.
However, and although I repeat that we will still have to wait, the truth is that this research would have managed to solve a challenge that has lasted many decades, and that at the time was considered practically impossible. We can think the same about thermal control, and about the challenges that later arise in the race to terahertz.
